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Title: Comparison of direct and indirect positron-generation by an ultra-intense femtosecond laser

An extensive comparison of the properties of positron beams produced by an ultra-intense femtosecond laser in direct and indirect schemes has been performed with two-dimensional particle-in-cell and Monte Carlo simulations. It is shown that the positron beam generated in the indirect scheme has a higher yield (10{sup 10}), a higher temperature (28.8 MeV), a shorter pulse duration (5 ps), and a smaller divergence (8°) than in the direct case (10{sup 9} yield, 4.4 MeV temperature, 40 ps pulse duration, and 60° divergence). In addition, it was found that the positron/gamma ratio in the indirect scheme is one order of magnitude higher than that in the direct one, which represents a higher signal/noise ratio in positron detection. Nevertheless, the direct generation method still has its own unique advantage, the so-called target normal sheath acceleration, which can result in quasi-monoenergetic positron beams that may serve in some specialized applications.
Authors:
 [1] ;  [2] ; ; ; ;  [3] ;  [1]
  1. School of Nuclear Science and Technology, Lanzhou University, Lanzhou 730000 (China)
  2. (China)
  3. Science and Technology on Plasma Physics Laboratory, Research Center of Laser Fusion, China Academy of Engineering Physics, Mianyang 621900 (China)
Publication Date:
OSTI Identifier:
22218559
Resource Type:
Journal Article
Resource Relation:
Journal Name: Physics of Plasmas; Journal Volume: 20; Journal Issue: 10; Other Information: (c) 2013 AIP Publishing LLC; Country of input: International Atomic Energy Agency (IAEA)
Country of Publication:
United States
Language:
English
Subject:
70 PLASMA PHYSICS AND FUSION TECHNOLOGY; 07 ISOTOPES AND RADIATION SOURCES; ACCELERATION; COMPARATIVE EVALUATIONS; COMPUTERIZED SIMULATION; LASER-PRODUCED PLASMA; LASERS; LIGHT TRANSMISSION; MEV RANGE; MONTE CARLO METHOD; PLASMA SIMULATION; POSITRON BEAMS; POSITRON DETECTION; POSITRONS; SIGNAL-TO-NOISE RATIO; TWO-DIMENSIONAL CALCULATIONS